This application proposes three studies that investigate the role of the stress in mediating alcohol's positive reinforcement effects. Alcohol's positive reinforcement is partly provided by the mesolimbic dopamine system. Corticosteroids (cort), stress hormones released during conditions of stress and after alcohol use, have been shown to moderate dopamine activation. A blockade of cort synthesis leads to decreased self administration of alcohol and other drugs of abuse, perhaps by disrupting the positive reinforcement and subjective experience of euphoria. To test this hypothesis in humans, three studies are proposed: 1) Study 1, with 23 subjects per condition, will cross alcohol/placebo with shock/no shock to determine if cortisol release is additive and to establish its effects on self- reported euphoria; and, 2) Study 2 will use a blockade of cortisol by Metyrapone to investigate the role of HPA activation in response to alcohol, stress and their interaction.